Harmonizing pg_bsd_indent parameter names

Attached patch harmonizes pg_bsd_indent's function parameter names, so
that they match the names used in corresponding function definitions.

I have been putting this off because I wasn't sure that the policy
should be the same for pg_bsd_indent. Is there any reason to think
that this will create more work down the line? It seems like it might,
due to some kind of need to keep pg_bsd_indent's consistent with
upstream BSD indent. But probably not. The patch is pretty small, in
any case.

I'd like to push this patch now. It's generally easier to be strict
about these inconsistencies. My clang-tidy workflow doesn't
automatically filter out various special cases requiring subjective
judgement, so leaving stuff like this unfixed creates more work down
the road.

-- 
Peter Geoghegan